The details and images -- bodies found in the street with hands still secured behind their backs, having been left there for weeks -- are evidence of the Russians breaking one of the most fundamental tenets of the law of war: not to execute prisoners. Residents have also described beheadings, gang rapes and other atrocities, setting off a race to secure evidence and investigate the troops responsible.
But it's a far legal reach to verify that evidence in a war zone, gain custody of a defendant, find the proper court of jurisdiction, and prove a case, according to U.S. military law experts. And America's own hesitancy to engage with international legal bodies, such as the International Criminal Court, in light of past concerns about how American troops might be viewed during the wars in Afghanistan and Iraq, only complicate U.S. assistance in bringing potential Russian war criminals to justice.
"It's not impossible, but it definitely is a challenge to get all these pieces lined up together," retired Army Col. Gary Corn, a former judge advocate general and general counsel to U.S. Cyber Command, said in an interview with Military.com.
All of the allegations have been unambiguously denounced by Russian officials from President Vladimir Putin on down as lies concocted by Ukrainian President Volodymyr Zelenskyy in cahoots with his ally, the U.S. And Russian officials have resorted to a version of whataboutism, pointing to civilian casualties during U.S. operations in the Middle East, to claim American officials lack any moral high ground.
The verified videos of the bodies of Ukrainian soldiers and civilians lying in the streets of Bucha and in the basements of blown-out buildings are nothing but propaganda theater, with crisis actors playing the parts of the dead, the Russians say.
Putin and his underlings have maintained that the invasion was justified to "de-Nazify" an illegitimate Ukrainian state, propped up by the U.S. and NATO, which posed a threat to Russia -- despite Russia's active shelling of the Babi Yar memorial, one of Ukraine's chief remembrances of the Holocaust.
In a sign of his contempt for the allegations against the Russian military, Putin issued a presidential decree April 18 honoring the 64th Motor Rifle Brigade for "mass heroism and valor, tenacity, and courage shown by the personnel in hostilities for the defense of the motherland and state interests during armed conflicts."
Ukraine's own charges of what happened when the Russians came to Bucha, northwest of the capital of Kyiv, have received initial validation from international investigative bodies and a report from on the ground in Bucha by the nonprofit Human Rights Watch research and advocacy group.
"The cases we documented amount to unspeakable, deliberate cruelty and violence against Ukrainian civilians," Hugh Williamson, HRW's Europe and Central Asia director, said in a statement issued with the report. "Rape, murder, and other violent acts against people in the Russian forces' custody should be investigated as war crimes."
Karim Khan, chief prosecutor of the International Criminal Court at the Hague, announced in February that his office is investigating allegations of war crimes in Ukraine; on an April 8 fact-finding visit to Bucha, he told reporters that "Ukraine is a crime scene."
"We're here because we have reasonable grounds to believe that crimes within the jurisdiction of the ICC are being committed," Khan said. But to make cases, "We have to pierce the fog of war to get to the truth," he added.
Finding the Right Court for War Crimes
The International Criminal Court in the Hague exists to prosecute violations of the various laws of armed conflict and the Geneva Conventions, and the United Nations has occasionally set up special tribunals. But Ukraine may have to take the judicial lead in bringing cases to trial.
"In theory, Ukrainian courts could try them," said Corn, a professor at American University's Washington College of Law and director of the school's Technology, Law and Security Program.
Although various governments have offered to help assemble evidence, the fog appeared to thicken at the U.N. Security Council session on April 5, where Russian Ambassador Vasily Nebenzya tossed off a few insults at Zelenskyy before getting to his main point, which was to accuse the U.S. of hypocrisy in leveling war crimes charges against the Kremlin.
In an Orwellian twist, Nebenzya charged Zelenskyy and his supporters with carrying out a "linguistic inquisition" to abolish the Russian language in Ukraine's Donbas region, where Russia has set up the rump People's Republics of Donetsk and Luhansk.
And anyway, Nebenzya added, "We're not acting like the Americans and their allies in Iraq and Syria, where they're razing entire cities to the ground."
He called on Security Council members not to be fooled by "the huge amount of lies against Russian soldiers and the military" drummed up by the U.S.
When it came his turn at the Security Council session, Ukraine Ambassador Sergiy Kyslytsya said that he would not dignify the "diabolical script" read by the Russian ambassador with a detailed response, but said it amounted to Nebenzya's "rather detailed application for a seat in hell."
But expecting the ICC to take up charges might be optimistic. The court takes on war crimes prosecutions when the nation that has the main responsibility -- in this case Russia -- "is unwilling or unable genuinely to carry out the investigation or prosecution" as stated in Article 17 of the Rome Statute, said retired Army Lt. Col. Michael Newton, a West Point graduate and former judge advocate general.
The United Nations Security Council also could convene a special tribunal, as happened in the former Yugoslavia and Rwanda, but Russia and China have a veto on the Security Council.
The U.S. is not a party to the treaty that created the ICC -- nor are Russia and Ukraine -- but the U.S. has the Uniform Code of Military Justice to deal with law of war violations by its troops, said Newton, who was part of a State Department team that helped to negotiate the 2002 Rome Statute.
"The idea is that the court [the ICC] is a last resort. If you have a functioning system that prosecutes your own, you don't need the ICC," said Newton, now a law professor at Vanderbilt University. "We bring them back for UCMJ trials, and that's what we do."
Ukrainian Prosecutor General Iryna Venediktova has said that Ukraine, with assistance from the U.S. State and Justice Departments, intends to prosecute war crimes cases against the Russians on its own, but she also has reserved the right to refer cases to the ICC.
Newton dismissed Russian attempts to assert a moral equivalence between how the U.S and Russian militaries conduct themselves on the battlefield as a "red herring."
"That's just not true," he said. "The U.S. has a duty to investigate and prosecute" war crimes and "it's non-negotiable."
Newton added that if the Russian allegations were true, then "why would you have seen, I don't know, Eddie Gallagher prosecuted?"
He referred to the controversial case of Navy SEAL and Chief Petty Officer Edward Gallagher, who was court-martialed under the UCMJ for numerous offenses, including stabbing to death an injured 17-year-old ISIS prisoner.
Gallagher was convicted of posing for a photograph with the corpse but acquitted of all other charges. Then-President Donald Trump intervened to reverse Gallagher's demotion in rank and also restored his right to wear the coveted SEAL Trident insignia.
Trump also pardoned two service members who had been convicted or accused of war crimes -- 1st Lt. Clint Lorance and Maj. Matthew Golsteyn -- but those cases should not be misconstrued as excuses for how the Russian military has operated in Ukraine, said retired Air Force Lt. Col Rachel VanLandingham, president of the National Institute of Military Justice.
"Russia shouldn't escape from accountability for its systematic campaign of barbaric war crimes due to claims of hypocrisy," VanLandingham, a professor at Southwestern Law School in Los Angeles, said in interviews and statements to Milltary.com. "Case-by-case imperfections in the American commitment to the laws and customs of war don't excuse Russia's complete and utter disregard of this law, and shouldn't distract from clear, unequivocal condemnation."
Mounting Evidence of Russian Crimes
Currently, Ukrainian and international investigative teams are seeking to document cases for potential war crimes prosecutions from the trail of carnage left by Putin's "special military operation" through the towns of Bucha, Borodianka, Chernihiv, Kherson, Hostomel, Irpin, Kharkiv and elsewhere.
The besieged southeastern port of Mariupol, described by United Nations Humanitarian Coordinator Martin Griffiths as the "epicenter of horror," continues to face Russian attacks. Russian forces have put the city under relentless bombardment, while mostly preventing civilians from fleeing and blocking International Red Cross aid convoys from access. Schools and hospitals have been rocketed while apartment blocks have been obliterated, with tenants crushed beneath the rubble
Satellite images from Maxar Technologies also appeared to show new mass graves in the town of Manhush just outside of Mariupol, The Associated Press reported Friday.
Mariupol Mayor Vadym Boychenko charged that the Russians are attempting to conceal "their military crimes" by taking the bodies of those killed in Mariupol and burying them in Manhush.
While stressing the need for investigations of atrocity allegations against the Russians and not making claims of equivalence, United Nations officials have also cautioned that Ukrainian soldiers may also have committed war crimes.
On April 5, Rosemary DiCarlo, a former State Department official and now under secretary general for political affairs at the U.N., addressed the Security Council on accountability for war crimes in Ukraine just before Ukrainian President Zelenskyy spoke virtually from Kyiv and showed a graphic video of dead and mutilated bodies in Bucha.
"Many credible allegations of serious violations" of international law and the laws of armed conflict in "areas recently retaken from Russia forces must not go unanswered," DiCarlo said.
"Ensuring accountability and justice for acts committed during the war will not be easy, but it is essential," she said, adding that "disturbing videos" had emerged showing "abuses of prisoners of war by both sides" -- the Ukrainians as well as the Russians.
She apparently referred to a video, verified by The New York Times and others, that surfaced in late March on a pro-Russian Telegram channel showing a group of soldiers wearing Ukrainian patches and blue arm bands standing over four troops wearing Russian uniforms and lying on a road.
Three of the four appear to have head wounds, and the fourth lies in a pool of blood gasping for air. "He's still alive. He's gasping," one of the standing soldiers says. Another soldier then points a rifle at the body and fires a total of three shots. The body stops moving, and someone off camera shouts "Slava Ukrayini!" -- "Glory to Ukraine!"
Ukrainian officials immediately said that the incident would be investigated. At an April 7 NATO news conference in Brussels, Ukrainian Minister of Foreign Affairs Dmytro Kuleba said, "I want to reassure you that Ukrainian army observes the rules of warfare. There might be isolated incidents of the violation of these rules and they will be definitely investigated."
Three U.S. military law experts interviewed by Military.com warned against drawing a "false equivalence" between the conduct of the Ukrainian and Russian militaries. The big difference is that the Ukrainians have pledged to investigate and potentially prosecute allegations of war crimes by their own soldiers, while the Russians have dismissed even the suggestion that their troops might be liable, they said.
And although the exact means may be up in the air, President Joe Biden insisted from the White House last week that ways must be found "to hold Putin accountable for his brutal and bloody war."
Russian forces driven back from their failed mission to take the capital of Kyiv have "left behind evidence of their atrocities and war crimes against the Ukrainian people -- it's so clear to the whole world now," Biden said.
Editor's note: This story has been updated to correct which program Corn is associated with.
-- Richard Sisk can be reached at Richard.Sisk@Military.com.